The present disclosure generally relates to systems and methods for locking dies. More particularly, the present disclosure relates to systems and methods for locking dies used in isothermal forging applications.
Many metallic materials having great high-temperature strength such as titanium and nickel-based alloys are characteristically difficult to process. One effective way of processing such materials is by isothermal forging, in which the forging die is heated to the forging temperature of the metal concerned.
Most isothermal dies are disk-shaped and are generally constituted of two disk-shaped die halves whose mating surfaces have been formed with die cavities. At the time of isothermal forging, the two die halves are mated with the work-piece to be forged disposed between them and the result, referred to as a die stack, is loaded into a forging press and heated. Typically, the die stack is secured in the forging press by a series of bolts that are manually tightened prior to heating the die stack. As die stack is heated the die stack experiences thermal expansion. Depending on the amount of thermal expansion and how tight the bolts securing the die stack are, the thermal expansion may cause the dies and/or connecting bolts to break. Alternatively, if the bolts are insufficiently tightened in an attempt to prevent the disk from breaking, the dies may be able to move relative to each other during the forging process.
Accordingly, what is needed is a method and system for locking dies in an isothermal forging process that prevents the dies from breaking due to thermal expansion while preventing the dies from moving.